An outbreak of the potentially debilitating Ross River virus in Victoria has continued to worsen, with authorities warning that another 155 people have been infected
Last week the state's chief health officer issued a warning about unusually high numbers of infections, noting that there had been 857 recorded case since January 1.
This week that tally has climbed again, to 1012.
The spread comes after heavy rainfall and warm weather across Victoria, which has created ideal breeding grounds for the mosquitoes that carry the virus.
Chief health officer Charles Guest said 1012 was nearly 10 times greater than the number of infections seen after major flooding in 2010 when there were only 103 notifications recorded.
"Recent rain and relatively warm weather has created conditions ideal for mosquito breeding and we have seen a major increase in mosquito numbers as a result," he said.
"This summer, we are now seeing the biggest increase of Ross River virus cases since the last major floods of 2010."
Symptoms include fever, headache, aching muscles, joints and fatigue. Some people will also develop a rash.
For most people it's considered a mild infection but in rare cases a person can experience symptoms for more than a year.
The Victorian Health Department last week warned there had been six people believed to have become infected in metropolitan Melbourne – in Casey and Frankston – areas where mosquitoes carrying the virus are not usually found.
None of those in Melbourne had travelled to regional areas where the virus is known to be present, suggesting they contracted it from mosquitoes locally.
A Health Department spokesman said there had been no further cases reported in Melbourne since last week, with all the new notifications from regional areas.
Loddon Mallee region feels the sting of insects
Hundreds of cases of Ross River virus have been reported in the Loddon Mallee region so far this year, making it the second worst-affected area in the state.
Loddon Mallee residents reported 238 infections by the beginning of this week, behind Hume with 329 cases, but well in front of the next closest region, the Grampians, where just 89 cases were recorded.
The figures come with a warning from Victoria’s chief health officer, Charles Guest, who said the total of 1012 Ross River notifications across the state was almost 10 times greater than after previous major flooding.
This summer, we are now seeing the biggest increase of Ross River virus cases since the last major floods of 2010.
“Recent rain and relatively warm weather has created conditions ideal for mosquito breeding and we have seen a major increase in mosquito numbers as a result.”
By comparison, Professor Guest said there were just 103 notifications of Ross River virus reported by mid-February 2011.
The City of Greater Bendigo is one of 11 high-risk and flood-affected Victorian councils now undertaking control measures for the first time through the treatment of mosquito breeding sites as part of a $4.6 million funding injection.
Control measures range from trapping mosquitoes to estimate numbers, testing sentinel chickens, using control agents to stop mosquito larvae from growing and fogging where numbers are excessive.
Professor Guest said simple steps to avoid bites and protect yourself against mosquito-borne diseases included ensuring insect screens fitted to doors and windows are in good condition, wearing long, loose-fitting clothing and using a suitable insect repellent.
He said mosquito numbers could also be reduced by getting rid of stagnant water around the home or at campsites.
“As mosquitoes can hatch quickly, water containers around the home should be emptied at least once a week,” he said.